1. Field of the Invention
The present invention relates to a solid-state image sensing device and method for manufacturing the same.
2. Related Art
A solid-state image sensing device configured by a PN junction photosensor and a charge transfer section has compatibility with a CMOS manufacturing process. This solid-state image sensing device is, therefore, manufactured on the same chip as that on which a CMOS circuit is formed. The CMOS circuit is employed as an output section or a peripheral circuit section in the solid-state image sensing device.
A conventional technique for the solid-state image sensing device of this type (for example, a technique described in Japanese Patent Application Laid-Open No. 1999-289075 (H11-289075)) will be described.
FIG. 11 is a cross-sectional view that exemplarily shows a conventional solid-state image sensing device 1 configured so that an image sensor section 2 that consists of a conventional PN junction photosensor section (hereinafter, “photosensor section”) 6 and a charge transfer section 8, and a CMOS circuit section 4 that includes an NMOS region 10 and a PMOS region 12 are formed on the same chip.
A first N type semiconductor region 24 is formed on a face of the photosensor section 6 within a first P well 18 formed on a face of an N type semiconductor substrate 14 so as to form a PN junction. A second N type semiconductor region 26 is formed on a face of the charge transfer section 8 within the first P well 18, and a charge transfer electrode 30 is formed on the second N type semiconductor region 26 through a gate insulating film 28. In the CMOS circuit section 4, an NMOS and a PMOS are formed in two wells, that is, a second P well 20 and an N well 22, respectively. The NMOS and the PMOS are isolated from each other by a shallow trench isolation insulating film 32. The NMOS includes a gate electrode 40, a gate insulating film 38, an N+ type diffusion layer 34, and an N type diffusion layer 36. The PMOS includes a gate electrode 50, a gate insulating film 48, a P+ type diffusion layer 44, and a P type diffusion layer 46.